The microRNA miR-30a blocks adipose tissue fibrosis accumulation in obesity
Pradip K. Saha, Robert Sharp, Aaron R. Cox, Rabie Habib, Michael J. Bolt, Jessica B. Felix, Claudia E. Ramirez Bustamante, Xin Li, Sung Yun Jung, Kang Ho Kim, Kai Sun, Huaizhu Wu, Samuel Klein, Sean M. Hartig
Pradip K. Saha, Robert Sharp, Aaron R. Cox, Rabie Habib, Michael J. Bolt, Jessica B. Felix, Claudia E. Ramirez Bustamante, Xin Li, Sung Yun Jung, Kang Ho Kim, Kai Sun, Huaizhu Wu, Samuel Klein, Sean M. Hartig
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Research Article Cell biology Metabolism

The microRNA miR-30a blocks adipose tissue fibrosis accumulation in obesity

Abstract

White adipose tissue (WAT) fibrosis occurring in obesity contributes to the inflammatory and metabolic comorbidities of insulin resistance and type 2 diabetes, yet the mechanisms involved remain poorly understood. Here, we report a role for the broadly conserved miRNA miR-30a as a regulator of WAT fibrosis and systemic glucose metabolism. Mice modified to express miR-30a at elevated levels in adipose tissues maintain insulin sensitivity coupled with reduced fatty liver disease when fed a high-fat diet. These effects were attributable to cell-autonomous functions of miR-30a that potently increase expression of adipocyte-specific genes. Proteomic screening revealed miR-30a limits profibrotic programs in subcutaneous WAT, at least in part, by repressing PAI-1, a dominant regulator of fibrinolysis and biomarker of insulin resistance. Conversely, mouse adipocytes lacking miR-30a exhibited greater expression of fibrosis markers with disrupted cellular metabolism. Lastly, miR-30a expression negatively correlates with PAI-1 levels in subcutaneous WAT from people with obesity, further supporting an antifibrotic role for miR-30a. Together, these findings uncover miR-30a as a critical regulator of adipose tissue fibrosis that predicts metabolically healthy obesity in people and mice.

Authors

Pradip K. Saha, Robert Sharp, Aaron R. Cox, Rabie Habib, Michael J. Bolt, Jessica B. Felix, Claudia E. Ramirez Bustamante, Xin Li, Sung Yun Jung, Kang Ho Kim, Kai Sun, Huaizhu Wu, Samuel Klein, Sean M. Hartig

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Figure 6

Knockout of miR-30a de-represses fibrosis genes and blocks adipocyte differentiation.

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Knockout of miR-30a de-represses fibrosis genes and blocks adipocyte dif...
(A) iWAT Sirius red staining and mean adipocyte size (μm2) measured across 4 fields of view (n = 3/group) of miR-30a–/– or miR-30a+/+ littermate controls after HFD feeding for 12 weeks. Scale bars: 50 μm. (B) Quantification of percentage of Picrosirius red staining (%area; n = 3/group, relative to miR-30a+/+). (C) Hydroxyproline content by mass spectrometry (n = 5–6/group). (D) Expression profiles of pro-fibrotic and metabolic genes (n = 7–8/group) in the iWAT of miR-30a–/– or miR-30a+/+ littermate controls after HFD feeding for 12 weeks. (E) Reverse phase protein array (RPPA) analysis performed on iWAT shown as fold change miR-30a–/–/miR-30a+/+. SVF-derived adipocytes were prepared from miR-30a+/+ and miR-30a–/– mice. (F) Differentiated miR-30a+/+ and miR-30a–/– cells were stained with ORO to characterize lipid accumulation. (G) Adipocytes were stained and imaged using deconvolution microscopy to identify mitochondria (red), lipid (green), and nuclei (blue). Scale bars: 50 µm. (H) Oxygen consumption rate (OCR) in differentiated miR-30a+/+ and miR-30a–/– mice with addition of oligomycin, carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone and antimycin-A/rotenone (n = 4/group). All data are represented as the mean ± SEM. *P < 0.05, by 2-way ANOVA with Tukey’s multiple-comparison test. (I) mRNA expression of selected adipocyte differentiation and fibrosis markers in SVF-derived adipocytes (n = 3/group). *P < 0.05, by 2-tailed, unpaired Student’s t test (A–E and I).